This study looks at whether a school-based version of the random, no-advance warning drug testing program will reduce drug use in high school athletes. Recognizing the high rate of substance abuse among young athletes and their 'role model' effect on other students, the US Supreme Court recently upheld a policy to randomly drug test students engaged in school-sponsored sports. Drug testing has the potential to deter adolescent substance abuse. It is gender-neutral, without ethnic bias and provides a potentially powerful environmental influence. Despite its legality and possible effectiveness, it hasn't been studied to know whether it is an effective prevention tool. Twenty-four schools who agree to implement mandatory testing as school policy but have never implemented this policy, will be randomly assigned to three years of either: 1) random drug testing or 2) a control period without testing. State-of-the-art testing will include same-gender physician specimen collectors, with specimen analysis using the most accurate analytical techniques to minimize false negative (which can reduce policy integrity) and false positive (which could mislabel students) results. Confidential questionnaires will be completed by student-athletes twice yearly to assess risk and protective factors for drug use and assess self-reported substance abuse. The role model effect of the surveillance program on non-athletes drug use will be assessed twice yearly by anonymous survey. Study findings will assist school districts evaluate whether drug testing could be an effective drug prevention method.